<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>async_write (1 of 8 overloads)</title>
    <link rel="stylesheet" href="../../../boostbook.css" type="text/css">
    <meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
    <link rel="home" href="../../../index.html" title="Asio">
    <link rel="up" href="../async_write.html" title="async_write">
    <link rel="prev" href="../async_write.html" title="async_write">
    <link rel="next" href="overload2.html" title="async_write (2 of 8 overloads)">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%">
    <tr>
        <td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../../asio.png"></td>
    </tr>
</table>
<hr>
<div class="spirit-nav">
    <a accesskey="p" href="../async_write.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u"
                                                                                               href="../async_write.html"><img
        src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png"
                                                                                            alt="Home"></a><a
        accesskey="n" href="overload2.html"><img src="../../../next.png" alt="Next"></a>
</div>
<div class="section">
    <div class="titlepage">
        <div>
            <div><h4 class="title">
                <a name="asio.reference.async_write.overload1"></a><a class="link" href="overload1.html"
                                                                      title="async_write (1 of 8 overloads)">async_write
                (1
                of 8 overloads)</a>
            </h4></div>
        </div>
    </div>
    <p>
        Start an asynchronous operation to write all of the supplied data to a
        stream.
    </p>
    <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <a class="link" href="../AsyncWriteStream.html"
                                             title="Buffer-oriented asynchronous write stream requirements">AsyncWriteStream</a><span
                class="special">,</span>
    <span class="keyword">typename</span> <a class="link" href="../ConstBufferSequence.html"
                                             title="Constant buffer sequence requirements">ConstBufferSequence</a><span
                class="special">,</span>
    <span class="keyword">typename</span> <a class="link" href="../WriteToken.html" title="Write token requirements">WriteToken</a> <span
                class="special">=</span> <a class="link"
                                            href="../asynchronous_operations.html#asio.reference.asynchronous_operations.default_completion_tokens"><span
                class="emphasis"><em>DEFAULT</em></span></a><span class="special">&gt;</span>
<a class="link"
   href="../asynchronous_operations.html#asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span
        class="emphasis"><em>DEDUCED</em></span></a> <span class="identifier">async_write</span><span
                class="special">(</span>
    <span class="identifier">AsyncWriteStream</span> <span class="special">&amp;</span> <span
                class="identifier">s</span><span class="special">,</span>
    <span class="keyword">const</span> <span class="identifier">ConstBufferSequence</span> <span
                class="special">&amp;</span> <span class="identifier">buffers</span><span class="special">,</span>
    <span class="identifier">WriteToken</span> <span class="special">&amp;&amp;</span> <span
                class="identifier">token</span> <span class="special">=</span> <a class="link"
                                                                                  href="../asynchronous_operations.html#asio.reference.asynchronous_operations.default_completion_tokens"><span
                class="emphasis"><em>DEFAULT</em></span></a><span class="special">,</span>
    <span class="keyword">typename</span> <span class="identifier">constraint</span><span
                class="special">&lt;</span> <span class="identifier">is_const_buffer_sequence</span><span
                class="special">&lt;</span> <span class="identifier">ConstBufferSequence</span> <span class="special">&gt;::</span><span
                class="identifier">value</span> <span class="special">&gt;::</span><span class="identifier">type</span>  <span
                class="special">=</span> <span class="number">0</span><span class="special">);</span>
</pre>
    <p>
        This function is used to asynchronously write a certain number of bytes
        of data to a stream. It is an initiating function for an <a class="link"
                                                                    href="../../overview/model/async_ops.html"
                                                                    title="Asynchronous Operations">asynchronous
        operation</a>, and always returns immediately. The asynchronous operation
        will continue until one of the following conditions is true:
    </p>
    <div class="itemizedlist">
        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                All of the data in the supplied buffers has been written. That is,
                the bytes transferred is equal to the sum of the buffer sizes.
            </li>
            <li class="listitem">
                An error occurred.
            </li>
        </ul>
    </div>
    <p>
        This operation is implemented in terms of zero or more calls to the stream's
        async_write_some function, and is known as a <span class="emphasis"><em>composed operation</em></span>.
        The program must ensure that the stream performs no other write operations
        (such as async_write, the stream's async_write_some function, or any other
        composed operations that perform writes) until this operation completes.
    </p>
    <h6>
        <a name="asio.reference.async_write.overload1.h0"></a>
        <span><a name="asio.reference.async_write.overload1.parameters"></a></span><a class="link"
                                                                                      href="overload1.html#asio.reference.async_write.overload1.parameters">Parameters</a>
    </h6>
    <div class="variablelist">
        <p class="title"><b></b></p>
        <dl>
            <dt><span class="term">s</span></dt>
            <dd><p>
                The stream to which the data is to be written. The type must support
                the AsyncWriteStream concept.
            </p></dd>
            <dt><span class="term">buffers</span></dt>
            <dd><p>
                One or more buffers containing the data to be written. Although the
                buffers object may be copied as necessary, ownership of the underlying
                memory blocks is retained by the caller, which must guarantee that
                they remain valid until the completion handler is called.
            </p></dd>
            <dt><span class="term">token</span></dt>
            <dd>
                <p>
                    The <a class="link" href="../../overview/model/completion_tokens.html" title="Completion Tokens">completion
                    token</a> that will be used to produce a completion handler, which
                    will be called when the write completes. Potential completion tokens
                    include <a class="link" href="../use_future.html" title="use_future"><code
                        class="computeroutput"><span class="identifier">use_future</span></code></a>,
                    <a class="link" href="../use_awaitable.html" title="use_awaitable"><code
                            class="computeroutput"><span class="identifier">use_awaitable</span></code></a>,
                    <a class="link" href="../yield_context.html" title="yield_context"><code
                            class="computeroutput"><span class="identifier">yield_context</span></code></a>,
                    or a function object with the correct completion signature. The function
                    signature of the completion handler must be:
                </p>
                <pre class="programlisting"><span class="keyword">void</span> <span
                        class="identifier">handler</span><span class="special">(</span>
  <span class="comment">// Result of operation.</span>
  <span class="keyword">const</span> <span class="identifier">asio</span><span class="special">::</span><span
                            class="identifier">error_code</span><span class="special">&amp;</span> <span
                            class="identifier">error</span><span class="special">,</span>

  <span class="comment">// Number of bytes written from the buffers. If an error</span>
  <span class="comment">// occurred, this will be less than the sum of the buffer sizes.</span>
  <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span
                            class="identifier">bytes_transferred</span>
<span class="special">);</span>
</pre>
                <p>
                    Regardless of whether the asynchronous operation completes immediately
                    or not, the completion handler will not be invoked from within this
                    function. On immediate completion, invocation of the handler will
                    be performed in a manner equivalent to using <a class="link" href="../post.html" title="post"><code
                        class="computeroutput"><span class="identifier">post</span></code></a>.
                </p>
            </dd>
        </dl>
    </div>
    <h6>
        <a name="asio.reference.async_write.overload1.h1"></a>
        <span><a name="asio.reference.async_write.overload1.completion_signature"></a></span><a class="link"
                                                                                                href="overload1.html#asio.reference.async_write.overload1.completion_signature">Completion
        Signature</a>
    </h6>
    <pre class="programlisting"><span class="keyword">void</span><span class="special">(</span><span class="identifier">asio</span><span
            class="special">::</span><span class="identifier">error_code</span><span class="special">,</span> <span
            class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span
            class="special">)</span>
</pre>
    <h6>
        <a name="asio.reference.async_write.overload1.h2"></a>
        <span><a name="asio.reference.async_write.overload1.example"></a></span><a class="link"
                                                                                   href="overload1.html#asio.reference.async_write.overload1.example">Example</a>
    </h6>
    <p>
        To write a single data buffer use the <a class="link" href="../buffer.html" title="buffer"><code
            class="computeroutput"><span class="identifier">buffer</span></code></a> function as follows:
    </p>
    <pre class="programlisting"><span class="identifier">asio</span><span class="special">::</span><span
            class="identifier">async_write</span><span class="special">(</span><span class="identifier">s</span><span
            class="special">,</span> <span class="identifier">asio</span><span class="special">::</span><span
            class="identifier">buffer</span><span class="special">(</span><span class="identifier">data</span><span
            class="special">,</span> <span class="identifier">size</span><span class="special">),</span> <span
            class="identifier">handler</span><span class="special">);</span>
</pre>
    <p>
        See the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput"><span
            class="identifier">buffer</span></code></a>
        documentation for information on writing multiple buffers in one go, and
        how to use it with arrays, boost::array or std::vector.
    </p>
    <h6>
        <a name="asio.reference.async_write.overload1.h3"></a>
        <span><a name="asio.reference.async_write.overload1.per_operation_cancellation"></a></span><a class="link"
                                                                                                      href="overload1.html#asio.reference.async_write.overload1.per_operation_cancellation">Per-Operation
        Cancellation</a>
    </h6>
    <p>
        This asynchronous operation supports cancellation for the following <a class="link"
                                                                               href="../cancellation_type.html"
                                                                               title="cancellation_type"><code
            class="computeroutput"><span class="identifier">cancellation_type</span></code></a>
        values:
    </p>
    <div class="itemizedlist">
        <ul class="itemizedlist" type="disc">
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">cancellation_type</span><span
                        class="special">::</span><span class="identifier">terminal</span></code>
            </li>
            <li class="listitem">
                <code class="computeroutput"><span class="identifier">cancellation_type</span><span
                        class="special">::</span><span class="identifier">partial</span></code>
            </li>
        </ul>
    </div>
    <p>
        if they are also supported by the <code class="computeroutput"><span class="identifier">AsyncWriteStream</span></code>
        type's <code class="computeroutput"><span class="identifier">async_write_some</span></code>
        operation.
    </p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%">
    <tr>
        <td align="left"></td>
        <td align="right">
            <div class="copyright-footer">Copyright © 2003-2022 Christopher M. Kohlhoff<p>
                Distributed under the Boost Software License, Version 1.0. (See accompanying
                file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
            </p>
            </div>
        </td>
    </tr>
</table>
<hr>
<div class="spirit-nav">
    <a accesskey="p" href="../async_write.html"><img src="../../../prev.png" alt="Prev"></a><a accesskey="u"
                                                                                               href="../async_write.html"><img
        src="../../../up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../home.png"
                                                                                            alt="Home"></a><a
        accesskey="n" href="overload2.html"><img src="../../../next.png" alt="Next"></a>
</div>
</body>
</html>
